Laser Sighting for Endoprosthesis Locking Bore Alignment

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Solution Overview

Problem

Existing methods for determining the position and orientation of locking holes in endoprostheses during implantation are inaccurate, cumbersome, and expose patients and surgeons to radiation, while mechanical aiming devices are bulky, complex, and expensive.

Innovation Solution

A medical device using non-parallel line lasers for precise optical sighting, directly coupled to the endoprosthesis, to indicate the position and orientation of boreholes, reducing radiation exposure and improving accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If radiographic imaging with Kirschner wires is used to determine locking hole position and orientation, then measurement precision is improved, but radiation exposure increases significantly

Engineering Contradiction:
Improveposition and orientation determination accuracyVSAvoidradiation exposure
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the mechanical/radiographic imaging system with an optical laser-based sighting device. The laser device projects visible laser lines that directly indicate the bore axis and locking hole positions, eliminating the need for radiographic imaging and Kirschner wires while providing equivalent or superior measurement precision without radiation exposure.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the physical parameter used for indication from invisible X-rays to visible laser light. This parameter change allows the surgeon to directly observe the bore axis and locking hole positions through visible laser lines, improving measurement precision while completely eliminating radiation exposure to patient and surgical team.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If mechanical aiming devices are used to indicate locking hole positions, then ease of operation is improved, but device complexity and cost increase

Engineering Contradiction:
Improveguidance for drillingVSAvoidmechanical aiming device structure
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical aiming devices with a simplified optical laser system. The laser device uses light projection instead of mechanical linkages, moving parts, and complex mechanical structures, thereby reducing device complexity while maintaining ease of operation through direct visual indication of drilling paths.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent extracts and eliminates the unnecessary mechanical components from traditional aiming devices. By using only the essential function of indicating bore positions through laser lines, the device removes complex mechanical structures, reducing overall device complexity while preserving the core guidance function.

Inventive Principle:
Principle #2Taking out (Extraction)

3Ease of operation

If mechanical aiming devices are positioned at considerable distance from the implant, then ease of operation is improved, but measurement precision deteriorates

Engineering Contradiction:
Improveaccessibility of aiming deviceVSAvoidlocking hole position indication accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent introduces a coupling structure as an intermediary between the laser device and the implant. This coupling structure directly attaches the laser device to the implant, eliminating the need for considerable distance positioning while maintaining ease of operation. The laser lines are projected directly from the implant location, ensuring high measurement precision without requiring the device to be positioned far from the implant.

Inventive Principle:
Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The device provides precise, compact, and cost-effective guidance for drilling bone bores, ensuring secure prosthesis fixation without radiation, with enhanced accuracy and ease of use.

Implementation Method 1

The optical sighting device has at least two separately spaced line lasers configured to emit at least two non-parallel laser beams

Methodology Applied
Scientific EffectLaser: Laser

Data Source

PatentEP3791813B1Medical device for determining the position and orientation of a bore for a locking means to be inserted into a locking opening of an endoprosthesis
Publication Date: 2026.03.25 AESCULAP AG
  • EP3791813B1 patent drawingFigure 1~2
  • EP3791813B1 patent drawingFigure 3~4
  • EP3791813B1 patent drawingFigure 5~7

AI summary

The present invention relates to a medical device (1) for determining the position and orientation of a drill axis (19, 21) of a bone bore to be inserted into a bone relative to a locking opening (16, 17) of an endoprosthesis (6) inserted into the bone, in particular an intramedullary nail or a revision hip stem (6), for a locking means locking the endoprosthesis (6) to the bone, which device (1) has a coupling structure (4) for position-determined indirect or direct coupling of the device (1) to the endoprosthesis (6) and an optical sighting device (5) for indicating the position and/or orientation of the drill axis (19, 21).